The Border Collie is a British breed of herding dog of the collie type of medium size. It originates in the region of the Anglo-Scottish border, and descends from the traditional sheepdogs once found all over the British Isles. It is kept mostly as a working sheep-herding dog or as a companion animal. It competes with success in sheepdog trials. It has been claimed that it is the most intelligent breed of dog.

The border collie is descended from landrace collies, a type found widely in the British Isles. The name for the breed came from its probable place of origin along the Anglo-Scottish border. Mention of the "collie" or "Colley" type first appeared toward the end of the 19th century, although the word "collie" is older than this and has its origin in the Scots language. It is also thought that the word 'collie' comes from the old Celtic word for useful. Many of the best border collies today can be traced back to a dog known as Old Hemp.